In contemporary computer based systems for controlling manufacturing and process industries, such as chemical plants, oil refineries, pulp and paper mills, steel mills, etc., there has typically existed a large range of different applications of different origin that have had to be integrated into a single control system. Further, a control system typically includes several computers connected through a communication network, where said applications are distributed in different configurations for different installations. Traditional methods for this integration have entailed extremely lengthy development times resulting, for example, in significant changes in requirements before such control programs have been completed and made ready for use. Another problem with traditional development methods is that it has been difficult and lengthy to update such control programs to include new requirements, such as the integration of additional and new applications. Writing and modifying control system programs to combine newer applications with older, existing applications has also been difficult, time consuming and expensive.
The adoption of object-oriented programming languages and methods has led to somewhat shorter development times, and made it somewhat easier to incorporate or integrate new applications.
There exists a tool that has been used for solving the problems mentioned above and that is the Component Object Model (COM). COM is described in The Component Object Model Specification available in the MICROSOFT™ MSDN Online Library on the web site maintained by Microsoft. Additional information about COM may be found in, amongst others, an article in Dr. Dobbs Journal December 1994 entitled The Component Object Model: Technical Overview.
WO-01/02953 entitled “Method of integrating an application in a computerized system” discloses a method for integration of many and various types of applications in a computerized system. This method is based on a concept where real world objects are represented as “composite objects”. Different facets of a real world object, such as its physical location, the current stage in a process, a control function, an operator interaction, a simulation model some documentation about the object, etc., are each described as different aspects of the composite object. A composite object is a container for one or more such aspects. Thus, a composite object is not an object in the traditional meaning of object-oriented systems, but rather a container of references to such traditional objects which implement the different aspects. Each aspect or group of aspects may be implemented by an independent software application, which provides its functionality through a set of interfaces that are accessible through the composite object. Another software application can thus query a composite object for a function associated with one of its aspects, and as a result obtain through the composite object, a reference to the interface that implements the function.
The use of containers and aspects in a process control system is also described in WO-03/032233 entitled “Data access method for a control system”.
Both these documents use containers and aspects that are provided based on COM objects.
Thus different tools have been provided for controlling industrial processes in a system in an efficient way. However, there may be a need for allowing control of a process provided in one system from another system.
One example of this is if there is a number of interconnected systems, which are to be monitored and controlled separately in the daytime, while at night control for all systems is to be provided from one of the systems. This should then be allowed to be performed in such a way that the night time operators should have the feeling that the connected systems are provided in one single system. The control should be possible to provide seamlessly and transparently.
There is therefore a need for providing the possibility to control from a first system a process running in a second system.